I have one of those annoying cupboards that used to hold the cylinder in the 2nd bedroom. It actually goes over the stairs and you have to climb up into it.
When a new combi boiler was fitted downstairs, I got rid of the cylinder in the cupboard and bought a couple of sets of black plastic shelves from Argos and put them in the cupboard and then i used plastic boxes with lids, those IKEA £4 zipped bags with carry handles - things like that and I stacked the shelves and put the Christmas trees in there.
It's worked so well that I've decided to put all the Christmas stuff (including jigsaws) in that cupboard as well as all the other sundry household stuff not used all year.
So I'd probably put your pillows in the IKEA £4 zipped bags. I put all my cold weather throws, clothes and accessories in them in the bottom of my wardrobe. The carry handles make it easy to grab them.
I've got another odd area at the top of my fitted wardrobe which is a tall, deep shelf which I'm going to designate the Halloween and possibly Easter/Spring cupboard and pack things away in boxes and bags.
Then hopefully I won't have to rip out the whole house for example, to find where I've squirrelled away the Halloween stuff!